About ScreenTools
What We Do
ScreenTools is a free collection of nine browser-based tools for the small jobs designers, developers, accessibility practitioners, students, and display shoppers need — checking a phone's exact resolution, computing pixel density, choosing a TV size, finding a dead pixel, picking a screen color, converting color formats, or checking WCAG contrast. Each tool runs in your browser. No upload, install, account, or paywall. Three physical-measurement tools (on-screen ruler, online protractor, printable ruler PDF) live on our sister site screenruler.online and surface as outbound cards on the home grid.
The ScreenTools lineup covers practical screen workflows: device specifications, dead-pixel testing, aspect-ratio math, pixel and physical-unit conversion, screen-size comparison, PPI calculation, pixel color picking, color-format conversion, and accessibility contrast checks. The full grid is documented in Our Free Online Tools below.
When a workflow needs physical on-screen calibration, ScreenTools links out to the ruler-focused sister site. This keeps the calculator, testing, and reference tools here focused while the physical measurement tools live on a surface built for that job.
How It Works
Most ScreenTools workflows depend on the same raw facts: resolution, diagonal size, pixel density, aspect ratio, viewport units, and display type. A 13-inch laptop and a 27-inch monitor can share the same resolution while their pixels are physically very different sizes, which is why PPI and DPI calculations matter for design handoff, print planning, and display shopping.
The calculators and tests run directly in the browser: enter dimensions, pick a device preset, start a screen test, or share a URL with the exact values encoded. For a full walkthrough, read our step-by-step guide.
Who Uses Our Tools
ScreenTools is used by people who reach for a quick web utility instead of installing an app: designers checking responsive breakpoints, developers converting CSS units, video editors resizing assets, display shoppers comparing PPI and viewing distance, support teams reproducing screen defects, and students checking device specs for class projects.
The common constraint is speed: open the tool, enter the values or start the test, and get a usable answer without signup, installation, or a heavy desktop app.
Supported Devices and Browsers
ScreenTools works in Chrome, Safari, Firefox, Edge, and any modern browser that supports standard web technologies. It runs on iPhones, Android phones, iPads, Android tablets, MacBooks, Windows laptops, Chromebooks, and desktop monitors. No plugins, extensions, or special permissions are needed.
Our device database includes pre-configured PPI values for iPhone 12 through iPhone 15, Samsung Galaxy S23 and S24 series, iPad Pro, iPad Air, iPad mini, Xiaomi Redmi, Realme, OPPO, Vivo, and Samsung Galaxy A-series devices popular in India, Indonesia, and Turkey.
Supported Languages
ScreenTools is available in 20 languages: English, Chinese (Simplified and Traditional), Spanish, French, German, Japanese, Korean, Hindi, Vietnamese, Thai, Turkish, Indonesian, Malay, Filipino, Czech, Romanian, Croatian, Serbian, and Sinhala. We continue to add new languages based on user demand.
Measurement and Calibration
ScreenTools keeps numeric screen workflows here and sends physical measurement workflows to screenruler.online. If you need an actual-size ruler, an angle check, or a printable ruler PDF, use the sister-site tools so calibration, reference objects, and print scaling stay in the place built for physical measurement.
Our Free Online Tools
Six free browser-based tools for screen specs, screen testing, unit conversion, sizing, and PPI/DPI calculations. Each one runs entirely in your browser — no install, no account, no paywall. Physical ruler, protractor, and printable-ruler workflows are linked as sister-site tools.
| Tool | Purpose | Best for | Price |
|---|---|---|---|
| Color Picker | Pick any color on your screen and convert between HEX, RGB, HSL, and HSV — instantly, in your browser. | Sample brand colors from any web page, sync to your palette, then export the HEX or HSL value straight into Figma, Sketch, or your design system. | Free |
| Device Specs | Detailed specs database for 69+ phones, tablets, and laptops. | Mobile developers, designers, phone shoppers | Free |
| Dead Pixel Test | Test your screen for dead, stuck, or hot pixels in 60 seconds. | Anyone receiving a new screen or repair | Free |
| Contrast Checker | Enter foreground and background colors. Get the WCAG contrast ratio and pass/fail for AA and AAA, normal and large text. Live preview. | Sanity-check CSS color pairs at component review time. The ratio tells you immediately whether a tweak still passes. | Free |
| HEX Converter | Type a color in any format (HEX, RGB, HSL, HSV) and see all four. Batch mode converts a whole list at once. | Convert a Figma brand palette into the four CSS-ready formats engineering needs, all at once with batch mode. | Free |
| Screen Size Calculator | Calculate screen size from resolution and DPI for any device. | Home theater builders, monitor shoppers | Free |
| Pixel Converter | Convert px to rem, em, pt, %, vw, vh — instant CSS unit converter. | Front-end developers, CSS work, print-design tuning | Free |
| Aspect Ratio Calculator | Calculate aspect ratios for video, images, and screens. | Video editors, social media designers, image sizing | Free |
| PPI Calculator | Calculate pixel density from screen size and resolution — Retina threshold + print DPI. | Display shopping, Retina threshold checks, and reverse-calculating pixels needed for print at any DPI | Free |
Built by Developers, for Everyone
ScreenTools started as a single screen ruler and grew into a small constellation of tools — built by a team of web developers who kept running into the same class of problem during design reviews and hardware prototyping: a quick measurement, a spec sheet, a pixel density check, a dead-pixel sweep, all needed in thirty seconds without leaving the browser. Existing solutions were inaccurate, required installs, or buried the utility under five layers of ads, so we built clean versions ourselves and made them all free. In 2026 we split the suite — the ruler-concept tools moved to a dedicated sister site (screenruler.online) so each surface stays focused.
The set expanded one adjacent need at a time — each tool added only when enough of our own daily work touched it. The project is actively maintained, with new device profiles, calibration objects, language coverage, and tool features shipping on a regular cadence.
Privacy & Data
Tool inputs, saved colors, and preferences stay in your browser and are not uploaded to our servers. We use analytics to understand how people use the tool so we can improve it, but we do not collect any personal information. Nothing on ScreenTools requires an account; we don't track individual users; we don't sell data to third parties. Read our full Privacy Policy for details.
Contact
Have a question, found a bug, or want to suggest a feature? We welcome your feedback. Leave us a message and we will get back to you.